Gooseneck and fifth-wheel hitch assemblies are well known and commonly used to couple a trailer to a tow vehicle. Gooseneck hitch assemblies generally couple to a hitch ball located in the bed of a tow vehicle, such as in a pick-up truck bed or on the bed of a flat-bed truck. The gooseneck hitch assembly includes an extension that extends from an underside of a forward end of the trailer to the hitch ball. The coupling between the gooseneck hitch assembly and the hitch ball allows rotational and pivotal movement of the trailer relative to the tow vehicle to accommodate turning of the vehicle and maneuvering over uneven terrain.
Fifth-wheel hitch assemblies are employed to accommodate similar towing applications to those of gooseneck hitch assemblies but operate somewhat differently. In a fifth-wheel hitch assembly, a kingpin is provided on the trailer extending downwardly from a forward end thereof. A fifth-wheel hitch is installed in or provided on the tow vehicle, such as in the bed of a pickup. The fifth-wheel hitch includes a receiver configured to accept the kingpin and to lockingly engage therewith. The fifth-wheel hitch enables relative rotational movement between the kingpin and hitch to accommodate turning of the vehicle. The fifth-wheel hitch may also enable pivotal movement of the trailer relative to the tow vehicle to accommodate uneven terrain.
A common drawback to towing trailers using gooseneck and fifth-wheel hitch assemblies is transfer of forces from the trailer to the tow vehicle that may cause the tow vehicle to buck or lurch forward and aft. The force transfer can be related to, for example, acceleration or deceleration of the tow vehicle that causes a bump or jerk to be felt by the tow vehicle occupants as the trailer moves slightly toward or away from the tow vehicle as allowed by flexure and/or coupler slack in the hitch assembly. A similar but generally cyclic bumping may also be encountered as the vehicle and trailer travel along a roadway due to a variety of forces acting on the tow vehicle and trailer. This force transfer can decrease the ride comfort of occupants in the tow vehicle and may decrease the stability and/or safety of the tow. A gooseneck hitch assembly configured to at least partially absorb or dampen relative movements between the trailer and tow vehicle would increase the comfort of tow vehicle occupants and would be an advantageous improvement in the art.
Another drawback of prior art designs is the restriction of trailer equipped with a kingpin to use with a fifth-wheel hitch. A hitch assembly that easily enables conversion of a kingpin-equipped trailer to a gooseneck-style hitch would be advantageous.